Charles River Reservation is a 17-mile-long (27 km) urban preserve and public recreation area located along the banks of the Charles River in Boston, Cambridge, Watertown, and Newton, Massachusetts. The reservation is managed by the Massachusetts Department of Conservation and Recreation. The portion of the reservation between the Charles River Dam and the Eliot Bridge is listed as a historic district on the National Register of Historic Places. This includes the park in the Back Bay neighborhood of Boston known as the Esplanade. The Charles River above the Watertown Dam is managed as the Upper Charles River Reservation.